Bionic fiber adsorptive material with multi-adsorption sites and preparation method and use thereof

Patent metadata

Field	Value
Publication number	US-11738329-B2
Application number	US-202117214942-A
Country	US
Kind code	B2
Filing date	Mar 29, 2021
Priority date	Feb 3, 2021
Publication date	Aug 29, 2023
Grant date	Aug 29, 2023

Abstract

The present invention provides a bionic fiber adsorptive material with multi-adsorption sites and a preparation method and use thereof, and the material is rich in multi-adsorption sites (N, O and S). The material is obtained by blending three polyethyleneimine polymers modified by multifunctional groups respectively with a carboxylated nanocellulose and graphene oxide, then adopting a coaxial spinning method based on a principle of imitating spider spinning, and then adopting a post-crosslinking technology. The material has a multilayer structure with the nanocellulose as a skeleton, the graphene oxide as an outer layer, and the three polyethyleneimine polymers modified by the multifunctional groups respectively as an inner layer, and a connection among the layers is a chemical bond connection. Densities of N, O and S adsorption sites of the material according to the present invention are all higher than 5 mmol/g.

First claim

What is claimed is:

1. A preparation method of a bionic fiber adsorptive material with multi-adsorption sites comprising the following steps:
step S1, preparation of a carboxylated nanocellulose: adopting a TEMPO/NaBr/NaClO oxidation system to oxidize a biomass fiber, and regulating an oxidation level by controlling reaction conditions to obtain the carboxylated nanocellulose;
step S2, preparation of a polyethyleneimine polymer modified by (ethylenedithio)diacetic acid containing N and S sites: performing a first amidation reaction of (ethylenedithio)diacetic acid with a polyethyleneimine at a first temperature to obtain polyethyleneimine polymer modified by (ethylenedithio)diacetic acid containing N and S sites;
step S3, preparation of a polyethyleneimine polymer modified by dopamine containing O and N sites: performing a second amidation reaction of a polycarboxylic acid with dopamine at a second temperature; when the second amidation reaction is complete, continuing to add polyethyleneimine to perform a third amidation reaction to obtain polyethyleneimine polymer modified by dopamine containing O and N sites; wherein the polycarboxylic acid is oxalic acid, citric acid or 1,2,3,4-butanetetracarboxylic acid;
step S4, preparation of a polyethyleneimine polymer modified by hyperbranched polycarboxylic acid containing N and O sites: performing a fourth amidation reaction of hyperbranched polycarboxylic acid with polyethyleneimine at a third temperature to obtain the polyethyleneimine polymer modified by hyperbranched polycarboxylic acid containing the N and O sites; and
step S5, blending the carboxylated nanocellulose obtained in the step S1, the polyethyleneimine polymer modified by (ethylenedithio)diacetic acid containing the N and S sites obtained in the step S2, the polyethyleneimine polymer modified by dopamine containing the O and N sites obtained in the step S3, the polyethyleneimine polymer modified by hyperbranched polycarboxylic acid containing the N and O sites obtained in the step S4, and graphene oxide by a blending method to prepare a spinning solution, continuously spinning the spinning solution to form a fiber with multiple functional groups at a speed of 1-4 cm/s by using a coaxial spinning method, spraying 5 wt % to 15 wt % of a crosslinking agent in a total fiber mass on the fiber by a spraying mode under vacuum filtration conditions with a vacuum having a degree of 0.01 MPa to 0.04 MPa to crosslink for 10-30 minutes, infiltrating the crosslinking agent into the fiber relying on the vacuum, and freeze-drying for 24-48 hours to obtain the bionic fiber adsorptive material with multi-adsorption sites; wherein the material is rich in multi-adsorption sites, that is, N, O and S sites that have chelating performance for heavy metal ions; adjusting content of each adsorption site in the material by regulating a ratio of each component in the spinning solution,
wherein the crosslinking agent is epichlorohydrin.

2. The preparation method according to claim 1 , wherein a specific operation of the preparation of the carboxylated nanocellulose described in the step S1 is as follows: dispersing the biomass fiber in water to prepare a biomass fiber mixture, then adding NaBr with a mole fraction of 1-5 mmol/g absolute dry fiber and TEMPO with a mole fraction of 0.1-0.5 mmol/g absolute dry fiber into the biomass fiber mixture in turn, and then adding an NaOH solution with a mass fraction of 10-30% to adjust the pH value to 10, adding an NaClO solution with a mole fraction of available chlorine of 6-30 mmol/g absolute dry fiber into the biomass fiber mixture under a mixed liquid surface, mixing the biomass fiber mixture and the NaClO solution well, reacting for 4-8 hours, continuing to add the NaOH solution during the reaction to maintain the pH value of 10 until the pH value no longer changes, and adding ethanol to terminate the reaction to obtain the carboxylated nanocellulose.

3. The preparation method according to claim 1 , wherein a specific operation of the preparation of the polyethyleneimine polymer modified by (ethylenedithio)diacetic acid containing N and S sites described in the step S2 is as follows: dispersing (ethylenedithio)diacetic acid in water, adding the polyethyleneimine with a molecular weight of 7000-70000 according to a molar ratio of (ethylenedithio)diacetic acid to the polyethyleneimine of 10:1-20:1, reacting for 4-8 hours at the first temperature, performing dialysis using a dialysis bag with a molecular weight cut-off of 500-2000 for 24-48 hours, so as to remove unreacted small molecules after performing the first amidation reaction, removing excess water by heating to adjust a concentration of a reaction product to 50 wt % to 90 wt % to obtain the polyethyleneimine polymer modified by (ethylenedithio)diacetic acid containing N and S sites.

4. The preparation method according to claim 1 , wherein a specific operation of the preparation of the polyethyleneimine polymer modified by dopamine containing O and N sites described in the step S3 is as follows: adding the polycarboxylic acid and dopamine into water according to a molar ratio of 1:1-3:1, reacting for 4-8 hours at the second temperature to prepare polycarboxylic acid-modified dopamine, then adding the polyethyleneimine with a molecular weight of 7000-70000 into a reaction system according to a molar ratio of polyethyleneimine to polycarboxylic acid of 1:10-1:20, continuing reacting for 4-8 hours, performing dialysis using a dialysis bag with a molecular weight cut-off of 500-2000 for 24-48 hours, so as to remove unreacted small molecules after performing the second amidation reaction and the third amidation reaction, removing excess water by heating to adjust a concentration of a reaction product to 50 wt % to 90 wt % to obtain the polyethyleneimine polymer modified by dopamine containing O and N sites.

5. The preparation method according to claim 1 , wherein a specific operation of the polyethyleneimine polymer modified by hyperbranched polycarboxylic acid containing N and O sites described in the step S4 is as follows: mixing trimethylolpropane, citric acid and p-toluenesulfonic acid and reacting at 135-150° C. under stirring conditions for 1.5-2.5 hours to obtain hyperbranched polycarboxylic acid; a molar ratio of the trimethylolpropane to the citric acid is 0.1:0.3-0.1:0.4 and an added mass of the p-toluenesulfonic acid is 0.8%-1.5% of a total mass of the trimethylolpropane and the citric acid; reacting the polyethyleneimine with the molecular weight of 7000-70000 and the hyperbranched polycarboxylic acid according to a mass ratio of 1:1-1:3 for 4-8 hours at the third temperature, and heating to evaporate water to adjust a concentration of a reaction product to 50 wt % to 90 wt % to obtain the polyethyleneimine polymer modified by hyperbranched polycarboxylic acid containing N and O sites.

6. The preparation method according to claim 1 , wherein the blending method comprises: blending the carboxylated nanocellulose obtained in the step S1, the polyethyleneimine polymer modified by (ethylenedithio)diacetic acid containing N and S sites obtained in the step S2, the polyethyleneimine polymer modified by dopamine containing O and N sites obtained in the step S3, the polyethyleneimine polymer modified by hyperbranched polycarboxylic acid containing N and O sites obtained in the step S4 and graphene oxide according to a mass ratio of 1:(1-10):(1-10):(1-10):(1-10).

Assignees

• Univ Guangxi

Inventors

• Zhu Hongxiang
• He Hui
• Wang Lei
• Wang Shuangfei
• Zhou Hang

Classifications

• B01J20/267 Primary

  Cross-linked polymers · CPC title

• B01J20/28023

  Fibres or filaments (fibres or filaments in the form of membranes B01J20/28038; B01J20/28007 takes precedence) · CPC title

• B01J20/3007

  Moulding, shaping or extruding · CPC title

• B01J20/3078 Primary

  Thermal treatment, e.g. calcining or pyrolizing · CPC title

• C02F1/285

  using synthetic organic sorbents · CPC title